Zagreb, Croatia and Tel Aviv — At least seven Israeli tourists were killed and dozens were reported injured in a terrorist bomb attack in Bulgaria today, with Israel immediately placing the blame on Iran.

The blast targeted buses at the the airport in Burgas, a city on the Black Sea coast and a major entry point for tourists heading to nearby resorts. It remains unclear if the explosion was from a suicide bomber or a bomb placed at the front of one of the buses.

Tourism is a major economic earner for Bulgaria, a country of around 7 million people that drew 8.7 million foreign visitors last year – almost 140,000 of them from Israel. Bulgaria has established a reputation among Israelis as a cheap place to get married and to gamble, according to Bulgarian journalist Petar Karaboev.

Security for Israeli tourists in Bulgaria had been tightened after a reported attempt to bomb a bus carrying Israelis to a ski resort near Sofia was foiled in January. That incident was thought to be linked to the fourth anniversary of the assassination of commander Imad Mughniyeh from the Iranian-allied Lebanese militant group Hezbollah.

Bulgaria's popularity with Israelis yet relative lack of experience with political violence may explain how the country became a terrorist target.

“It could have happened anywhere in the world [but] Bulgaria is particularly vulnerable as the police have no anti-terrorism experience,” says Anthony Georgieff, a Bulgarian journalist and the author of a book on Jewish Bulgaria.

Political terrorism is unknown in post-Communist Bulgaria. The last politically-linked bomb attacks were carried out in the mid-1980s during a period of clashes between the Communist regime and the Muslim minority. The government’s attempts to force Bulgarian identity on a Turkish minority led both to an exodus of ethnic Turks from the country and to a number of bombings, most notoriously on a train near Sofia. Bulgarians still debate whether these were the works of Turkish terrorists or agent provocateurs from the shady Committee for State Security.

Bulgaria's minorities

Bulgaria has a substantial Muslim population – around 10 percent of the population according to the2011 census, which may well be an underestimate. But the Muslim population is overwhelmingly moderate. Religious extremism is rare in the Balkans as a whole, despite a history of ethnic conflict overlaid with religious differences. While there have been reports of jihadi cells and even training camps established in Macedonia, Kosovo, and Bosnia, they do not hold sway among the population as a whole – and there have been no such allegations made in Bulgaria.

Meanwhile, Bulgaria’s tiny Jewish community is extremely well-integrated, says Mr. Georgieff. It officially numbers 5,000 people, but he estimates that 2,000 may be a more accurate number if mixed marriages are taken out of the equation, making them perhaps the smallest recognized ethnic minority in the country.

Anti-semitism is almost unheard of in Bulgaria, according to Georgieff. “While occasionally extremist parties, including Ataka ['Attack'] which is represented in parliament, has engaged in almost medieval anti-Semitism, it’s not very popular with the population,” he says.

Many Bulgarians feel an affinity with Israel partly due to pride over their country’s stance in World War II, when pressure from the general population, civic organizations, and the Bulgarian Orthodox Church (a potent national symbol), blocked the deportation of Bulgarian Jews ordered by the country’s Nazi allies. Deportation, however, continued in Bulgarian-occupied zones of Yugoslavia and Greece.

Israel points to foreign hand

Israel has already pointed to foreign actors. Israeli officials and analysts said the strike in Burgas was part of an ongoing terrorist campaign by Tehran and its Lebanese militant ally, Hezbollah.

In a statement, Prime Minister Netanyahu suggested the timing was pegged to the 18th anniversary of the bombing of a Jewish community center in Buenos Aires that killed 85 people. Argentina issued an arrest warrant for Mr. Mughniyeh in 1999 in relation to the attack.

"Iran’s murderous terrorism continues to attack innocents," Mr. Netanyahu said. "This is an Iranian terror attack that is spreading throughout the entire world. Israel will respond with force."

Several Israeli tourist destinations and diplomatic missions have been targeted in the last year, but many have been thwarted. Just last week, authorities in Cyprus said they arrested a Lebanese man believed to be planning an attack against Israeli tourist targets in the island nation. This is in addition to recent attempts to attack Israeli targets in Thailand and Azerbaijan, and an almost-successful attack on the wife of a diplomat in India.

Iran is also accused by Israeli and local authorities of being behind those attacks. Iran, meanwhile, has accused Israel of sponsoring a covert campaign to assassinate its nuclear scientists and attack military installations around the country.

Some analysts said Hezbollah may be involved in today's attack because it has been seeking revenge for the 2008 assassination of Mughniyeh, Hezbollah’s military chief and the architect of 2006 war against Israel. The Lebanese militant group accused Israel of responsibility of the car bombing in Syria that killed Mughniyeh.